Optical element

Abstract

The present invention provides an optical element, which comprises: (a) a substrate, (b) a first surface on one side of the substrate wherein said first surface comprises a plurality of prism columnar structures with rounded peaks and the curvature radii of the rounded peaks are in the range from 3 μm to 20 μm, and (c) a second surface on the other side of the substrate wherein the second surface can be a plane surface or with concave-convex structures.

What is claimed is: 
     
         1 . An optical element, comprising
 (a) a substrate;   (b) a first surface on one side of the substrate wherein said first surface comprises a plurality of prism columnar structures with rounded peaks and the rounded peaks have curvature radii in the range from 3 μm to 20 μm, and   (c) a second surface on the other side of the substrate wherein the second surface is a plane surface or has concave-convex structures.   
     
     
         2 . The optical element as claimed in  claim 1 , wherein at least two of the prism columnar structures are non-parallel to each other. 
     
     
         3 . The optical element as claimed in  claim 2 , wherein said non-parallel prism columnar structures are intersecting or non-intersecting. 
     
     
         4 . The optical element as claimed in  claim 1 , wherein the second surface has concave-convex structures. 
     
     
         5 . The optical element as claimed in  claim 4 , wherein the second surface has concave-convex structures that do not contain diffusion beads. 
     
     
         6 . The optical element as claimed in  claim 4 , wherein the second surface has concave-convex structures that contain diffusion beads. 
     
     
         7 . An optical element, comprising:
 (a) a substrate;   (b) a first surface on one side of the substrate wherein said first surface comprises a plurality of prism columnar structures with rounded peaks and the rounded peaks have curvature radii in the range from 3 μm to 20 μm, and   (c) a second surface on the other side of the substrate wherein the second surface has concave-convex structures, wherein the prism columnar structures have a glass transition temperature less than 40° C.   
     
     
         8 . The optical element as claimed in  claim 7 , wherein the organic particles are uniformly distributed in the resin coating in a single layer. 
     
     
         9 . The optical film as claimed in  claim 1 , wherein in the case that the first surface of the substrate does not have any structure, the optical film has a haze not less than 3%, as measured according to JIS K7136. 
     
     
         10 . An optical element, comprising:
 (a) a substrate;   (b) a first surface on one side of the substrate wherein said first surface comprises a plurality of prism columnar structures with rounded peaks and the rounded peaks have curvature radii in the range from 3 μm to 20 μm, and   (c) a second surface on the other side of the substrate wherein the second surface is a plane surface or has concave-convex structures,   wherein the prism columnar structures have an abrasion loss less than 100 mg, as tested according to ASTM D4060 (CS-10 wheel, 1,000 g, 1,000 cycles).   
     
     
         11 . The optical element as claimed in  claim 10 , wherein the prism columnar structures can pass an HB Pencil Hardness Test, as tested according to JIS K-5400. 
     
     
         12 . A direct lighting backlight module, comprising an optical element as claimed in any of  claims 1  to  11 .